Enzymes: “Helper” Protein molecules

1. Enzymes:“Helper” Protein molecules s1

2. Flow of energy through life • Life is built on chemical reactions s2

3. + + s3 Chemical reactions of life • Processes of life • building molecules • synthesis • breaking down molecules • digestion

4. enzyme + enzyme + Nothing works without enzymes! • How important are enzymes? • all chemical reactions in living organisms require enzymes to work • building molecules • synthesis enzymes • breaking down molecules • digestive enzymes • enzymes speed up reactions We can’t live without enzymes! s4

5. + enzyme enzyme + Examples • synthesis • digestion

6. Enzymes are proteins • Each enzyme is the specific helper to a specific reaction • each enzyme needs to be the right shape for the job • enzymes are named for the reaction they help • sucrase breaks down sucrose • proteases breakdown proteins • lipases breakdown lipids • DNA polymerase builds DNA Oh, I get it! They end in -ase s6

7. s10 Enzyme vocabulary • Enzyme • helper molecule • Substrate • molecule that enzymes work on • Enzyme-substrate complex • enzyme & molecule temporarily joined • Active site • part of enzyme that substrate molecule fits into

8. substrate product enzyme active site Enzymes aren’t used up • Enzymes are not changed by the reaction • used only temporarily • re-used again for the same reaction with other molecules • very little enzyme needed to help in many reactions

9. It’s shape that matters! • Lock & Key model • shape of protein allows enzyme & substrate to fit • specific enzyme for each specific reaction

10. 1 2 3

11. What affects enzyme action • Correct protein structure • correct order of amino acids • why? enzyme has to be right shape • Temperature • why? enzyme has to be right shape • pH (acids & bases) • why? enzyme has to be right shape

12. More about Enzymes: What Affects Enzymes

13. What affects how well an enzyme works? • Correct protein structure • correct order of amino acids • why? enzyme has to be right shape • Temperature • why? enzyme has to be right shape • pH • why? enzyme has to be right shape

14. Enzyme concentration • Effect on rates of enzyme activity • as increase amount of enzyme = increases how fast the reaction happens • more enzymes = more frequently they collide with substrate

15. What’s happening here?! reaction rate amount of enzyme Enzyme concentration

16. Substrate concentration • Effect on rates of enzyme activity • as increase amount of substrate = increases how fast the reaction happens • more substrate = more frequently they collide with enzyme

17. What’s happening here?! Substrate concentration reaction rate amount of substrate s17

18. What’s happening here?! 37° Temperature reaction rate temperature

19. Temperature • Effect on rates of enzyme activity • Optimum temperature • greatest number of collisions between enzyme & substrate • human enzymes = 35°- 40°C (body temp = 37°C) • Raise temperature • denature protein = unfold = lose shape • Lower temperature T° • molecules move slower • decrease collisions s19

20. What’s happening here?! pH stomachpepsin intestinestrypsin reaction rate 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH

21. pH • Effect on rates of enzyme activity • pH changes protein shape • most human enzymes = pH 6-8 • depends on where in body • pepsin (stomach) = pH 3 • trypsin (small intestines) = pH 8 s21

22. SHAPE! For enzymes…What matters?